Revision 0:566fc5f530fe, committed 2012-05-02

Comitter:

janwesterkamp

Date:

Wed May 02 06:01:00 2012 +0000

Commit message:

Changed in this revision

diff -r 000000000000 -r 566fc5f530fe main.cpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/main.cpp	Wed May 02 06:01:00 2012 +0000
@@ -0,0 +1,103 @@
+#include "mbed.h"
+#include "parser.h"
+#include "string"
+#include "list"
+
+Serial pc(USBTX, USBRX);    // initialize RS232 via USB
+
+DigitalOut prg_activity_led(LED1);     // some LED to show activity
+DigitalOut rx_activity_led(LED2);
+DigitalOut tx_activity_led(LED3);
+DigitalOut message_led(LED4);
+
+// we need some storage for the messages we want to send and receive
+string singleSendMessageBuffer;
+string singleReceiveMessageBuffer;
+// and a buffer for those messages, until they are processed
+list<string> sendMessagesBuffer;
+list<string> receiveMessagesBuffer;
+
+
+// Interupt Routine to read in data from serial port
+void Rx_interrupt() {
+    rx_activity_led=!rx_activity_led;
+    // Loop just in case more than one character is in UART's receive FIFO buffer
+    while (pc.readable()) {
+        char c = pc.getc();
+        unwrap_protocol(&c, &singleReceiveMessageBuffer, &receiveMessagesBuffer);
+        // pc.putc(c); // echo
+    }
+    return;
+}
+
+
+// Interupt Routine to write out data to serial port
+void Tx_interrupt() {
+    char c;
+    int finished = WRAP_SEND;
+    int messageAvailable = !sendMessagesBuffer.empty();
+
+    tx_activity_led=!tx_activity_led;
+
+    // Loop to fill more than one character in UART's transmit FIFO buffer
+    while (  pc.writeable() && messageAvailable && (finished == WRAP_SEND)) {
+        finished = wrap_protocol( &c, &singleSendMessageBuffer, &sendMessagesBuffer );
+        if (finished != WRAP_ABORT)
+            pc.putc(c);
+    }
+
+    //tx_activity_led=0;
+    return;
+}
+
+
+int main() {
+
+    string sendString;
+
+    pc.baud(115200);        // other high speed: 921600
+
+    // Setup a serial interrupt function to receive data
+    pc.attach(&Rx_interrupt, Serial::RxIrq);
+    // Setup a serial interrupt function to transmit data
+    pc.attach(&Tx_interrupt, Serial::TxIrq);
+    // enable interrupt
+    NVIC_EnableIRQ(UART1_IRQn);
+
+    set_time(0);            // needed to initialize rtc
+
+    while (1) {
+        prg_activity_led = !prg_activity_led;       // toggle LED
+        time_t seconds = time(NULL);    // get current time
+
+        //printf("Time as a string = %s\r\n", ctime(&seconds));
+
+        if (!receiveMessagesBuffer.empty()) {
+            //pc.printf("\r\nMessage: %s\r\n", receiveMessagesBuffer.front().c_str());
+
+            sendString = "Message '";
+            sendString += receiveMessagesBuffer.front().c_str();
+            sendString += "' received at ";
+            sendString += ctime(&seconds);
+            sendString += "\r";
+
+            sendMessagesBuffer.push_back(sendString);
+            receiveMessagesBuffer.pop_front();
+
+        } else {
+            //sendString = "Hallo Welt!\r\n";
+            sendString = ctime(&seconds);
+            sendString += "\r";
+            sendMessagesBuffer.push_back(sendString);
+        }
+        
+        
+        // trigger sending interrupt
+        char c;
+        int finished = wrap_protocol( &c, &singleSendMessageBuffer, &sendMessagesBuffer );
+        if (finished != WRAP_ABORT)
+            pc.putc(c);
+
+        wait(1); // wait and don't flood the RS232
+    }
+}

diff -r 000000000000 -r 566fc5f530fe mbed.bld
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/mbed.bld	Wed May 02 06:01:00 2012 +0000
@@ -0,0 +1,1 @@
+http://mbed.org/users/mbed_official/code/mbed/builds/737756e0b479

diff -r 000000000000 -r 566fc5f530fe parser.c
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/parser.c	Wed May 02 06:01:00 2012 +0000
@@ -0,0 +1,113 @@
+/*
+ *
+ */
+
+#include "mbed.h"
+#include "parser.h"
+
+int wrap_protocol(char *c, string *message, list<string> *messages, char header, char footer, char dle ) {
+
+    static int state = 0;
+    static int dle_state = 0;
+    static int index;
+    static int size;
+
+
+    switch (state) {
+        case 0: // start sending a header if there is a valid message available
+            if (!messages->empty()) {
+                *message =  messages->front();
+                messages->pop_front();      // now that we have the message, delete it from the list
+                index = 0;                  // initialize sending the actual message
+                size = message->size();
+                state = 1;
+                *c = header;
+                return WRAP_SEND;
+            }
+            return WRAP_ABORT;
+
+        case 1:
+            if ((size == 0) || (index==size)) {
+                *c = footer;
+                state = 0;
+                return WRAP_FINISHED;
+            }
+
+            *c = (*message)[index];
+
+            if ( dle_state == 1 ) {
+                dle_state = 0;
+                index++;
+                return WRAP_SEND;
+            }
+
+            if ( (*c == header) || (*c == footer) || (*c == dle) ) {
+                dle_state = 1;
+                *c = dle;
+                return WRAP_SEND;
+            }
+
+            index++;
+            return WRAP_SEND;
+    }
+
+    // if we reach this point, something went wrong!
+    return WRAP_ABORT;
+}
+
+void unwrap_protocol(char *c, string *buffer, list<string> *messages, unsigned int max_message_size,
+                     unsigned int max_messages, char header, char footer, char dle ) {
+
+    // these are needed for the internal state of the function
+    // they are also the reaseon, why this function can only be used in exactly one location
+    // i.e. the interrupt routine for receiving characters from the RS232
+    static int state = 0;
+    static int dle_state = 0;
+
+    switch (state) {
+        case 0:
+            if (*c == header) {
+                message_led=!message_led;
+                state = 1;
+            }
+            return;
+
+        case 1:
+            if (*c== header && dle_state==0) {
+                // new header that is not escaped will set e new message start
+                buffer->clear();
+                return;
+            }
+            if (*c == footer && dle_state==0 ) {
+                // a frame end is only a frame end, if the footer is not escaped
+                messages->push_back( *buffer );
+                buffer->clear();
+                state = 0;
+                message_led=!message_led;
+                return;
+            }
+
+            // check length of buffer; clear, if too large; restart search for header!
+            if (buffer->length() > max_message_size) {
+                // prevent buffer overflows if someone is flooding us with characters
+                buffer->clear();
+                state=0;
+                return;
+            }
+
+            if (*c == dle && dle_state==0) {
+                // the next character is "escaped" and is part of the message
+                dle_state = 1;
+                return;
+            }
+
+            // probably the easiest and quickest way of resetting the dle_state
+            dle_state = 0;
+
+            // in all other cases, we found a new character and append it to the buffer
+            *buffer += *c;
+    }
+}
+
+
+

diff -r 000000000000 -r 566fc5f530fe parser.h
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/parser.h	Wed May 02 06:01:00 2012 +0000
@@ -0,0 +1,32 @@
+/*
+ *
+ */
+
+#ifndef _PARSER_H_
+#define _PARSER_H_
+
+#include "string"
+#include "list"
+
+#define WRAP_SEND   1
+#define WRAP_ABORT  2
+#define WRAP_FINISHED  3
+
+#define HEADER_CHAR 'A'
+#define FOOTER_CHAR 'B'
+#define DLE_CHAR '+'
+
+void unwrap_protocol(char *, string *buffer, list<string> *messages,
+                     unsigned int max_message_size = 255, unsigned int max_message = 5,
+                     char header=HEADER_CHAR, char footer=FOOTER_CHAR, char dle=DLE_CHAR);
+
+
+int wrap_protocol(char *c, string *buffer, list<string> *messages,
+                   char header=HEADER_CHAR, char footer=FOOTER_CHAR, char dle=DLE_CHAR);
+
+
+// these have to be declared somewhere else for consistency
+extern DigitalOut message_led;
+
+
+#endif